Google Analytics on Multiple Domains

I saw a similar topic covered, but I am still having a problem with Google Analytics. I installed the plugin on one site I created for a client, and it works fine. I tried to install the same plug in, with different settings, on a site I created for another client, but the access profile and default tracking domain listed are for the wrong client. I tried creating a new API key, clearing the cache, but it didn’t work. How can I have Google Analytics track info for the site I’m working on? Thank you!